A wooden cube of side 10 cm and specific gravity 0.8 floats in water with its upper surface
horizontal. What depth of the cube remains immersed? What mass of aluminimum of specific gravity 2.7
must be attached to
(I) The upper surface,
(II) The lower surface so that the cube will be just immersed?

Hi,

To calcuate depth immersed, use buoyancy = weight of cube.
For part 1, buyoant force will only be appled on the cube and wieght would increase.
Buyancy = Volume of cube * Density of water = Total weight
For part 2, buyant force will be applied both on cube and aluminium mass and weight would increase too.
Buoyancy = Volume of ( cube + aluminium) * Density of water = Total weight

thanks

Approved

Yes, it should be multipled with ‘g’. Sorry, my bad........................................................................................................................................................................................................................................................................